Induction voltage regulator



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INDUCTION VOLTAGE REGULATOR Filed May 26, 1960 6 Sheets-Sheet 2 June1965 M. G. LEONARD ETAL 3,189,856

INDUCTION VOLTAGE REGULATOR Filed May 26, 1960 6 Sheets-Sheet 3 IIO\Fig.4.

I'M-* l June 15, 1965 Filed May 26. 1960 M. G. LEONARD ETAL INDUCTIONVOLTAGE REGULATOR Fig.6.

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June 15, 1965 M. s. LEONARD ETAL 3,139,856

mnucnon VOLTAGE REGULATOR Filed May 26, 1960 6 Sheets-Sheet 5 aoosnus H9. l5.

NEUTRAL 3 o 5' FINISH our: TURN TURNS June 15, 1965 M. G. LEONARD ETALINDUCTION VOLTAGE REGULATOR 6 Sheets-Sheet 6 Filed May 26. 1960 mom OmIlllflltlllLTll United States Patent INDUCTION VOLTAGE REGULATOR MerrillG. Leonard, Brookfield, Ohio, and John Astleford,

Jr., Hickory Township, Mercer County, Pa., assignors to WestinghouseElectric Corporation, East Pittsburgh,

Pa., a corporation of Pennsylvania Filed May 26, 1960, Ser. No. 32,018 7Claims. (Cl. 336-120) Thisinvention relates to electrical inductiveapparatus and more particularly to induction voltage regulators.

A conventional induction voltage regulator comprises a primary windingdisposed on a rotor member whose position can be varied with respect toan associated secondary winding disposed on a stationary stator core.The primary winding of the induction regulator is normally connected inparallel with an input circuit whose alternating current Voltage is tobe controlled or regulated and the secondary winding is normallyconnected in series with the output circuit of the regulator in order tointroduce a voltage component which is either additive or opposing withrespect to the input voltage of the regulator.

The construction of a conventional induction regulator and the meanswhich have been employed in the past for controlling its operation haveseveral important disadvantages. For example, in order to reduce thethrough voltage drop introduced by a conventional induction regulatorwhen the regulator is in the neutral position and the mutual inductancebetween the primary and secondary windings is at a minimum, a tertiarywinding is provided on the rotor member which is short-circ-uited toreduce the effective impedance of the secondary winding of the regulatorin the latter position. In addition, in .a conventional inductionregulator, it is well known that a vibratory torque of twice thefrequency of the alternating current being carried by the regulator isdeveloped in the rotor member of the regulator and may be transmitted tothe stationary parts of the regulator to produce an objectionable orundesirable noise level.

It is therefore desirable to provide an improved construction for aninduction voltage regulator and an improved means for controlling theoperation thereof which either reduces or substantially eliminates theabove disadvantages and provides several other advantages.

It is an object of this invention to provide a new and improvedinduction voltage regulator.

Another object of the invention is to provide a new and improved meansfor controlling the operation of an induction voltage regulator.

A further object of this invention is to provide an improved inductionregulator having primary and secondary windings in which the impedanceof the secondary winding is reduced when the regulator is in the neutralposition and which does not require the use of a tertiary winding.

A still further object of this invention is to provide an improvedinduction regulator in which the sound level is reduced.

A more specific object of the invention is to provide an improvedbearing arrangement for induction voltage regulators.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

For a fuller understanding of the nature and objects of the invention,reference should :be had to the following detailed description taken inconnection with the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view illustrating the manner in which aninduction regulator of the type disclosed may be mounted andinterconnected with an associated source of alternating current, such asa distribution transformer, in an electrical distribution system.

FIGURE 2 is a top plan view of the induction regulator shown in FIGURE 1with the cover removed and certain other parts either partially shown oromitted.

FIGURE 3 is a front elevational view partly in section of the inductionregulator shown in FIGURES 1 and 2.

FIGURE 4 is a partial side elevational view, partly in section, of theinduction regulator shown in FIGURES 1 through 3 illustrating thedetails of construction of the rotor member of said regulator.

FIGURE 5 is a partial bottom plan view of the induction regulator shownin FIGURE 4, illustrating the manner in which the rotor member is drivenby the associated driving means.

FIGURES 6 through 9 illustrate different bearing arrangements which maybe employed with the induction regulator shown in FIGURES 1 to 5.

FIGURES 10 through 12 illustrate the construction of a conventionallimit switch which may be employed with the induction regulator shown inFIGURES 1 through 5.

FIGURES 13 and 14 are diagrammatic views illustrating the principles ofoperation of the induction regulator shown in FIGURES 1 through 5 fordifferent operating positions of the rotor member thereof.

FIGURE 15 is a set of curves illustrating the different voltages whichresult in the secondary winding of the induction regulator shown inFIGURES 1 through 5 for different operating positions of the rotormember thereof, and

FIGURE 16 is an overall diagrammatic view illustrating the connection ofthe induction regulator shown in FIGURES 1 through 5, with theassociated distribution transformer and with its associated controlcircuit or equipment.

Referring now to the drawings and FIGURES 1 and 16 in particular, thereis illustrated an induction voltage regulator 30 which may beconveniently utilized with an associated source of alternating current,such as the distribution transformer 20, in an electrical power systemor distribution system. In this instance, the induction regulator 30 isshown mounted adjacent to the associated distribution transformer 20 ona common utility pole 29 and interconnected therewith in order tomaintain the voltage supp-lied to a load circuit by the distributiontransformer 20 at substantially a predetermined value or within asubstantially predetermined operating range. The transformer 20 may beof any conventional type and may include a primary or high voltagewinding 2-1 and a secondary or low voltage winding 31, as shownschematically in FIGURE 16. The primary or high voltage terminals 22 and23 at the ends of the primary winding 21 of the transformer 20 may beconnected to an associated electrical power system or source ofalternating current voltage (not shown), while the secondary or lowvoltage terminals 24 and 2-6 at the ends of the secondary winding 31 ofthe transformer 21 are connected to the input termi nals 32 and 34,respectively, of the induction regulator 30, as shown in FIGURES l and16. The midpoint or mid-tap of the secondary winding 31 of thetransformer 20 is illustrated as being connected to a ground connection,as indicated at 27. The output terminals 36 and 38 of the inductionregulator 30 are connected to a load circuit, as indicated at the loadconductors L1 and L2, respectively. For three-wire operation of thelatter load circuit, a third load conductor L3 may optionally beconnected to the ground connection or neutral terminal 27 of thetransformer 20.

In general, the induction voltage regulator 30 comprises a primarywinding 37, which is disposed on an associated rotor member 39, and asecondary winding 35, which oomprises the first and second secondarywinding sections or coils 35A and 353, respectively, and which isdisposed on an associated stationary stator core which will be describedin detail hereinafter.

The primary winding 37 is connected across or in parallel with the inputterminals 32 and 34 of the regulator by the flexible leads The firstsecondary winding section 35A is connected in series circuitrelationship with the load conductor L1 between the terminals 32 and 36of the regulator 30 by the leads S1 and S3, respectively, while thesecond secondary winding section of coil 35B is'c-onnected in seriescircuit relationship with the load conductor L2 between the terminals 34and 33 of the regulator 30 by the leads or conductors S2 and 54,respectively, in order to permit substantially balanced regulation ofthe voltage of a three-wire load circuit when the induction regulator 30is applied on a system of that type. The relative positions of theprimary and secondary windings 37 and 35, respectively, is varied byenergizing either the first or second drive motors 6t and 70,respectively, which are mechanically coupled to the rotor member 39 bythe mechanical linkage indicated generally at ML in FIG- URE 16. Theenergization of the drive motors so and 7%, which may be of anyconventional type, such as the shaded pole type, and which include themain windings 62 and '72, respectively, is controlled, in turn, inresponse to the output voltage of the induction regulator 30 at theterminals 36 and38 by the control circuit or means 4%, which isconnected in circuit relation with the drive motors 6 0 and 70 throughthe disconnect plug member 8 1 as shown in FIGURE 16. In order toprovide the necessary electrical energy for the operation of the drivemotors 6t? and "70, which are arranged to rotate the rotor member 39 inopposite directions and to provide a voltage signal to the controlcircuit 40 which is proportional to or varies with the output voltage ofthe induction regulator 30 at the terminals 36 and 58, the control orisolating transformer is connected in circuit relation with saidregulator. In particular, the transformer 59 comprises, in thisinstance, a primary winding 52 which is connected across the outputterminals 36 and 3d of the regulator 39 at the load conductors L1 andL2, respectively, the first and second secondary windings 5d and 56,respectively, which are connected in circuit relation with the drivemotors 7t) and 60, respectively, and a third secondary winding 53 whichis connected in circuit relation with the control circuit 40 through thedisconnect plug member 8% to supply a voltage sensing signal to saidcontrol circuit.

In order to limit the travel of the rotor member 3? when either thedrive motor 60 or the drive motor 7% is energized by the control circuit443 from the secondary Windings 56 or 54, respectively, of thetransformer 56, the first and second limit switches LS1 and LS2,respectively, shown diagrammatically in FIGURE 16 are actuated by themovement of the mechanical linkage or coupling ML to prevent the controlcircuit 4'8 from further energizing either the drive motor 60 or thedrive motor 76' when the travel of the rotor member 39 has reachedpredetermined operating positions in either direction of rotation.

In general, the control circu'itdti operates to maintain the outputvoltage of the induction regulator 30 at substantially a predeterminedvalue or within substantially a predetermined operating'range orbandwidth by energizing either the drive motor 69 with the drive motor7t? to rotate the rotor member 39 whenever the output voltage of theinduction regulator 34) deviates from substantially a predetermineddesired value or from a predetermined desired operating range.

Referring to FIGS. 2 through 5 and 13 and 14, the overall construct-ionand arrangement of parts of the induction regulator 39 is illustrated.In general, the regulator 3% comprises the stator magnetic core $0 onwhich the secondary winding 3-5 is disposed, the rotor member 39 onwhich the primary winding 3-7 is disposed and which is adapted forangular rotation with respect to the stator core 99, the control circuit40, the disconnect plug member 80, the transformer 5t and the drivemotors 6t and 4 70, which are all disposed and assembled in the casingor tank 23 and substantially immersed in a fluid dielectric, such as theinsulating oil whose level is indicated at 133 in PEG. 3,

In particular, the casing 28 includes a cover member 65 which isremovably secured to the side wall portion of the casing 28 by thelifting eye bolt member 152 and the beam member 3154, the lower portionof the eye bolt member 152 being adapted to engage a threaded portion ofthe beam member 154. In order to rernovably secure the beam member 154to the inside of the casing 23, the bracket members 156 are secured orWelded to the inside of the casing 28 adjacent to the upper end ofv theside wall portion thereof and include recess portions to accommodate theends of the beam member 154, The bracket members 156 cooperate with thecotter pins or bolts 158 to restrain any movement of the ends of thebeam member 54. In order to provide means for mounting the inductionregulator 30 on an associated utility pole or other location the bracketmember 42 may be secured to the side wall portion of the casing 28, asbest shown in FIGS. 2 and 3. In order to insulate the input terminals32- and 34 and the output terminals 36 and 38 of the induction regulator3i) as said terminals pass through the side wall portion of the casing28, the latter terminals may include conventional bushing members of anysuitable type,

as indicated in FIGS. 2 and 3. The flexible leads 43 of the primarywinding 37 and the leads S1 and S4 of the secondary winding sections 35Aand 35B are connected to the inner ends of the conductor portions of therespective terminals 32,, 3d. 36 and 38 of the induction regulator 3%,as best shown in FIGS. 2 and 3.

Referring now to FIGS. 3, 4, l3 and 14, the stator magnetic core 9% isgenerally cylindrical in configuration and includes a central opening orbore 53 in which the rotor member 39 is disposed for angular rotationand which in this instance is substantially circular in cross section.The stator magnetic core comprises a plurality of stacked laminations orpunchings formed from a suitable magnetic material, such as sheets ofhot rolled silicon steel or sheets of silicon-iron and aluminum-ironalloys containing from 1 to 7% silicon and from 1 to 10% aluminum,respectively, the sheets of the latter alloys having a cube texture,either doubly-oriented or randomly oriented wherein the major volumetricproportion of the grains have their cube faces parallel to the surfaceof the sheet and the cube edges of the cube grains are parallel to therolling direction and transverse thereto in the doubly oriented materialor the cube grains may have their edges randomly distributed in therandomly oriented material. One such doubly oriented cube texturedsilicon-iron alloy is that disclosed in copending application Serial No.681,333, filed August 30, 1957, which is assigned to the same assigneeas the present application.

After the laminations which form the stator magnetic core member 9% havebeen stacked or assembled, as best shown in FIGS. 3 and 4, thelaminations are preferably impregnated with a suitable thermosettingresin, such as an epoxy resin, which is then cured in place to bond saidlaminations together and form a unitary member. The latter method hasbeen found to insure proper alignment of the different laminations whichmake up the stator magnetic core )6. The stator magnetic core includes aplurality of substantially rectangular longitudinal slots 6-4 in whichare disposed the first and second secondary winding sections 35A and35B, respectively, of the secondary winding 35 and which arecircumferentially displaced from one another by substantially equaldistances around the inner opening 53 of the stator core member fiti. inthis instance, the stator magnetic core 96 includes four symmetricallydisposed slots 64 which are displaced from one another by an angle ofsubstantially 90 with respect to a central longitudinal axis of theopening 53 in said stator magnetic core. As indicated in FIGS. 13 and14, the first and second secondary winding sections or coils 35A and358, respectively, are each disposed in a pair of the stator slots 64 atopposite sides of the stator magnetic core 90 to form first and secondmagnetic poles in said stator core whenever current flows through saidsecondary Winding sections.

Each of the secondary winding sections 35A and 353 comprises a pluralityof conductor turns which may be in any suitable form, such as conductorstra to provide the necessary current carrying capacity in said windingsections. The conductor turns of each of the secondary winding sections35A and 35B form individual closed loops which may be preformed and thenassembled in the stator slots 64 of the stator core 98. As previouslymentioned, the ends of the secondary winding section 35A are brought outof the casing 28 to the terminals 32 and 36, while the ends of thesecondary winding section 33B are brought out of the casing 28 to theterminals 34 and 38. It is to be noted that during the operation of theinduction regulator 39 when current flows through the secondary windingsection 35A, the current instantaneously flows in opposite directionsthrough the active portions of the conductor turns which are disposed inthe upper and lower stator slots 64 associated with the secondarywinding section 35A. Similar current directions exist in the ditferentactive portions of the secondary winding section 3513.

Referring to FIGS. 13 and 14, it is to be understood that the secondarywinding sections or coils 35A and 35B may be held in place in therespective tator slots 64 by special insulation pieces, such as wedges,which are fitted into the grooves 65 provided on each side of the statorslots 64 adjacent to the opening 53 in the stator core 90.

In order to provide bearing support for the rotor member 39 and mountingsupport for the stator core 90 and the rotor member 39, as well as forcertain other parts of the induction regulator 30, the upper and lowerstator end bell members 132 and 134, respectively, are provided at theupper and lower ends, respectively, of the stator core 98. The upper andlower stator end bell members 132 and 134, respectively, are rigidlysecured to the stator core 91) by suitable fastening means such as thethrough bolts or rivets 176, as best shown in FIGS. 2 and 4. The throughbolts or rivets 176 which pass through the openings or holes 68 providedat the corners of the stator core 90 may be provided with associatedinsulating tubes or sleeves in order to reduce the eddy current losseswhich would otherwise result in the stator core 90.

In order to prevent relative movement of the upper and lower stator endbell members 132 and 134, respectively, with respect to the stator core90, the stator core 90 which is substantially rectangular in crosssection includes the projecting portions 180 at the respective cornersthereof which are adapted to be received by the corresponding openings179 in the corners of the associated stator end bell members and preventmovement of the latter type after said end bell members are assembledwith the stator core 90.

The corners of the stator core 90 are curved or formed as arcuateportions 138 which match and fit the inner periphery of the upper andlower stator end bell members 132 and 134, respectively, where thelatter members are in contact with the stator core 90.

In order to provide mounting support for the stator core 98, the rotormember 39 and certain other parts of the induction regulator 30 aspreviously indicated, the upper and lower stator end bell members 132and 134, respectively, are provided with the mounting arms 135 and 137,respectively, as best shown in FIGS. 2, 3 and 4. In this instance, theupper and lower mounting arms 135 and 137, respectively, includeopenings to receive the upper and lower supporting stud members 182 and186, respectively. The upper and lower stud members 182 and 186,respectively, are supported by the bracket member 172 which is rigidlysecured to the inside of the casing 28 by suitable means, such aswelding or bolts. The lower stud members 186 are secured or fastened tothe bracket member 172 by suitable means such as welding, while theupper stud members 182 are removably secured to the bracket member 172by suitable means, such as small brackets 183 and bolts 185, tofacilitate assembly of the stator core 90 on the bracket 172.

In order to reduce the ambient temperature range to which the controlcircuit or means 40 is subjected during the operation of the inductionregulator 30 and to reduce the temperature compensation required in saidcontrol means, the inside of the casing 28 is divided into first andsecond compartments or portions by the barrier or partition members 162and 163, which are disposed or mounted as best shown in FIGS. 2 and 3 onthe side of the bracket member 172 away from the stator core 90. Thebarrier members 162 and 163 are preferably formed from a material, suchas pressboard, which is both electrically and thermally insulating, inorder to reduce the circulation of the fluid dielectric between the twocompartments formed by said barrier members and to reduce the heattransfer between the fluid dielectric which is disposed in both of thecompartments inside the casing 28. The control circuit or means 40 whichis disposed in the compartment on the side of the barrier members 162and 163 away from the compartment in which the stator core 90 and therotor member 39 are disposed is, therefore, subjected to a smaller andlower operating range of temperatures. It is also to be understood thatthe control means 40 may be disposed in a separate compartment insidethe casing or tank 28 underneath the drive motors 60 and and the controltransformer with a thermal barrier disposed between the control means 40at the bottom of the casing and the balance of the regulator parts. Incertain applications, the control means 40 may be disposed in a separatecompartment which is attached or secured to the outside of the casing4t). In an arrangement of the latter type, the additional compartmentwould not have to be filled with the same fluid dielectric as the casing28.

In order to provide mounting support for the drive motors 6i) and 7t)and the mechanical coupling between said drive motors and the rotormember 39, the channel member 174 is secured to the lower stator endbell member 1334 by suitable fastening means, such as screws or bolts.The drive motors 60 and 70 are secured to one end of the channel member174 by suitable fastening means, such as the bolt 175, while thetransformer 50 is secured to the other end of the channel member 174 bysuitable fastening means, such as the rivets 177. The lug portions 143which extend downwardly from the lower stator end bell member 134 afterit is assembled with the stator core may include openings to providebearing support for the worm 122, which forms part of the mechanicalcoupling between the rotor member 39 and the drive motors 6t and 70. Theupper stator end bell member 132 may be also provided with correspondinglug portions 139 in order to make the upper stator end bell memberinterchangeable with the lower stator end bell member 134. It is to beunderstood that the lug portions 139 of the upper stator end bell member132 may be omitted in a particular application.

In order to reduce any vibration which results during the operation ofthe induction regulator 30 and which might originate with the drivingmeans associated with the rotor member 39 from being transmitted to thebracket member 172 and in turn to the casing 28, the upper and lowersupporting stud members 182 and 186, respectively, which support theupper and lower stator end bell members 132 and 134, respectively, areprovided with the sleeve or vibration isolating members 184, which areformed from a suitable resilient, elastomeric, rubberlike material, suchas the type known to the trade as nitrile rubber. The sleeve members 184function to strucamasse turally isolate the vibration which wouldotherwise be transmitted to the casing 23 and which might cause anobjectionable sound level during the operation of the regulator 39. Dueto the resilient nature of the material from which the sleeve membersare formed, the vibrations which result during the operation of theinduction regulator are either partially or completely absorbed by thesleeve members 184. 7 Similarly to the stator core 90,the rotor member39 comprises a plurality of stacked laminations or punchings formed froma suitable magnetic material, such as hot rolled silicon steel or othermagnetic materials of the type mentioned previously in connection withthe stator core 90. After the laminations which make up the rotor member39 are stacked or assembled, the laminations are preferably impregnatedwith a suitable thermosetting resin, such as an epoxy resin, which isthen cured in place to form a unitary member in which the differentlaminations which make up the rotor member 39 are maintained in properalignment. The rotor member 39 is provided with at least one pair ofsubstantially rectangular slots 4-9 and 51 which are disposed onopposite sides of the rotor member 39, the longitudinal slots 49 and 51being circumferentially displaced from one another by'an angle ofsubstantially 180 with respect to a central longitudinal axis of therotor member 39. The width of each of the rotor slots 49 and 51 isgreater than the circumferential spacing around the opening 53 in thestator core 9% between the adjacent stator slots 64 in order to increasethe effective magnetic reluctance in each of the magnetic paths aroundthe portion of the conductor turns of the secondary winding sections Aand 35B which are disposed in each of the stator slots 64, as will beexplained in detail hereinafter, for certain operating positions of therotor member 39.

Since the rotor member 39 is not provided with a through shaft forreasons which will be discussed here inafter, the upper and lower rotorend bell members or spider members 1% and 192, respectively, aredisposed at the upper and lower ends, respectively, of the rotor member39. The upper and lower end bell members 1% and 192 are secured to theupper and lower ends of the rotor members 39 by the through belts orrivets 157 which pass through the openings 57 provided in thelaminations which make up the rotor member 39. The through bolts orrivets 157 may also be provided with associated insulating tubes orsleeve members 194 in order to reduce the eddy current losses in therotor member 39. The upper and lower stub shaft portions 11% and 112,respectively, of the rotor member 39 may be formed as integral axialextensions of the rotor end bell members 190 and 192, respectively, orsaid shaft portions may be formed separately and then assembled withsaid rotor end bell members.

Similarly to the secondary winding sections 35A and 35B, the primarywinding 37 includes a plurality of conductor turns which are disposed inthe slots 49 and 51 of the member 39 to form a closed loop, the ends ofsaid primary winding being connected by the flexible leads 43 to theterminals 32 and 34 of the induction regulator 39. The absence of ashaft through the laminations which make up the rotor member 39 resultsin an increased crosssectional area of the magnetic material in thecentral portion of the rotor member 39 around which the conductor turnsof the primary winding 37 are wound and, along with the increased widthof the rotor slots 49 and 51, permits a more compact primary windingstructure and a more compact rotor member 39 to thereby reduce theoverall size and weight of the induction regulator fill. it is to benoted that upper and lower insulating channel members 46 and associatedinsulating side channel members 47 may be provided in the slots 49 and51 of the rotor member 39 to electrically insulate the primary winding37- from the laminations which make up the rotor member 39. When currentflows through the pri- 8 mary winding 37, magnetic poles are formed atthe opposite ends of the rotor member 39 between the adjacent rotorslots 49 and 51, as best shown in FIGS. 13 and 14.

In order to support the rotor member 39 and to maintain the rotor member39 in proper alignment inside the opening or bore 53 in the associatedstator core 90, the upper and lower bearing members 146 and 148,respectively, are disposed in the upper and lower bearing housings 142and 166, respectively, of the upper and lower stator end bell members132 and 134, respectively. The upper and lower bearing members 146 and143, respectively, are of the split ring sleeve type and include theinternally tapered portions 113 and 115, respectively. The taperedportions 113 and 115 of the upper and lower bearing members 145 and 143,respectively, bear against the matching tapered portions 111 and 117 ofthe upper and lower stub shaft portions and 112, respectively, in orderto apply a frictional force to said shaft portions which results in africtional torque which opposes or attenuates the vibratory torque whichresults during the operation of the induction regulator 3% The latterreduction in the net vibratory torque which might otherwise betransmitted to the casing 28 of the induction regulator 39 results in anoverall reduction in the sound level of the regulator 30. In order tomaintain the tapered portions 113 and 115 of the upper and lower bearingmembers 146 and 148, respectively, in contact with the tapered portions111 and 117, respectively, of the upper and lower shaft portions 116 and112, respectively, the biasing spring 144 is provided around the uppershaft portion 110 and is restrained by the upper bearing housing 142 toexert a downward force against the upper bearing member 146 and therotor member 39.

The upper and lower bearing members 146 and 148, respectively, areformed from a suitable material, such as high temperature molded nylon,and are arranged to be self-adjusting or self-centering with respect tothe rotor member 39 and its associated upper and lower shaft portions11d and 112, respectively. In the bearing arrangement shown in FIG. 4,the clearances between the outer diameter or circumference of thebearing members 146 and 14% and the inside diameter or circumference ofthe associated bearing housings 142 and 166, respectively, are arrangedto be negligible. Because of the tapered inner portions 113 and 115 ofthe bearing members 146 and 148, respectively, and because of the splitor saw cut in each of the bearing members 146 and 148, which is similarto the split or saw cut 147 shown for the alternate bearing member 146in FIG. 7, the bearing members 146 and 148 are adapted for axialmovement with respect to the upper and lower shaft portions 110 and 112,respectively, in order to maintain the rotor member 39 in vertical andradial alignment with the inside opening or bore 53 of the stator core90. It is to be noted that where the dielectric fluid provided in thecasing 28 is an insulating oil, adequate lubrication would be assuredfor the bearing members 146 and 148 since said bearing members areimmersed in the fluid dielectric.

Referring to FIGS. 6 through 9, two difierent bearing arrangements areillustrated which may be substituted for the bearing arrangement shownin FIG. 4 in certain applications. In particular, referring to FlGS. 6and 7 the first alternate bearing arrangement is shown which is similarto the bearing arrangement shown in FIG. 4 eX- cept that means areprovided for adjusting the position of the upper shaft portion 110 andthe rotor member 39 with respect to the inner opening or bore 53 or" thestator core 99. The bearing member 146 is similar to the hearing member146 shown in FIG. 4 and may include the saw cut or split, indicated at147 in FIG. 7, to permit axial movement of the bearing member 146. Ametallic ring or sleeve is provided around the outer circumference orperiphery of the bearing member 146', as indicated at 145 in FIGS. 6 and7, to prevent damage to the hearing member 146' by the adjusting screwsand the radially biasing spring 149, which are disposed in the bearinghousing 142' to exert radially inward forces against the outer peripheryor circumference of the bearing member 146".and its metallic supportingring or sleeve 145. .The bearing member 146 also includes an internallytapered portion 113' which is maintained in contact with the taperedportion 111 of the upper shaft portion 110 by the axially biasing spring144 to substantially eliminate any radial or axial clearance between thebearing member 146' and the tapered portion of the upper shaft portions110. It should be noted that the sleeve or ring 145 permits axialmovement of the bearing member 146' in response to the downward forceexerted against it by the biasing spring 144. A radial clearance isprovided, however, between the outer diameter or circumference of themetallic ring 145 and the inner diameter or circumference of themodified bearing housing 142, as shown in FIGS. 6 and 7, to permitpositioning of the bearing member 146 and the upper shaft portion 110 bymeans of two adjusting screws 140 and the radially biasing spring 149 tothereby position the rotor member 39'within the opening 53 of the statorcore 90. The lug portions 141 on the metallic ring 145 are provided oneach side of the upper adjusting screw 140 to prevent rotation of thebearing member 146 in place. In summary, the bearing arrangement shownin FIGS. 6 and 7 provides means for adjusting the position of the uppershaft portion 110 and the rotor member 39 and for centering said rotormember within the inner opening or bore 53 of the stator core 90. 1

Referring now to FIGS. 8 and 9, a second alternate bearing arrangementis illustrated which is similar to the bearing arrangement shown inFIGS. 6 and 7 except that the bearing member 146" does not include aninternally tapered portion like that of the bearing member 146'. Inother words, the bearing member 146' is a straight bearing rather than atapered bearing and includes three adjusting screws 140, rather than aradially biasing spring and two adjusting screws as does the bearingarrangement shown in FIGS. 6 and 7. The bearing member 146" alsoincludes a saw cut or split 136, as shown in FIG. 9, to permittightening of the bearing member 146" around the modified upper shaftportion 118 by means of the adjusting screws 140 spaced at 120 anglesaround the bearing. Similarly to the bearing arrangement shown in FIGS.6 and 7, the bearing member 146" includes two lug portions 141' whichare disposed on opposite sides of the upper adjusting screw 140 shown inFIG. 9 to prevent rotation of the bearing member 146 within the modifiedbearing housing 142". Similarly to the hearing arrangement shown inFIGS. 6 and 7, the bearing arrangement shown in FIGS. 8 and 9 permitsmanual centering of the rotor member 39 within the inner opening or bore53 of the stator core 90 by adjustment of the adjusting screws 140.

Referring now to FIGS. 4 and 5, the mechanical coupling between thedrive motors 60 and 7t and the rotor member 39 will now be described.The drive motors 60 and 70 are arranged to drive a common tandem shaftmember 178 in opposite directions when actuated by the control circuitor means 40. The tandem drive shaft 178 is mechanically coupled to theshaft 181 by the gear train 126, as best shown in FIG. 5. The worm 122is pinned or otherwise secured to the shaft 181 for rotationtherewithand the bearing members 18 9 which provide rotatable supports for theshaft 181 are disposed in the lug portions 143 of the lower stator endbell member 134 as previously mentioned. The worm 122, in turn, drives aconventional worm gear 124 which is secured or pinned to the lower shaftportion 112 of the rotor member 39 for rotation therewith. When eitherthe drive motor 60 or the drive motor 70 is energized by the controlcircuit or means 40, the rotor member 39 is driven through themechanical coupling or linkage just described to rotate substantially 90in either one or the other direction from a neutral position of therotor member 39 with respect to a central vertical axis of the rotormember 39. In order to limit the angular travel of the rotor member 39by either the drive motor 60 or the drive motor 70, as previouslymentioned, the first and second limit switches LS1 and LS2,respectively, are provided to be actuated by the projecting members 195which extend. downwardly from the lower rotor end bell member 192 toengage either the limit switch LS1 or the limit switch LS2 in certainpredetermined operating positions of the rotor member 39. In particular,the limit switches LS1 and LS2 as shown in FIGS. 10 through 12 eachincludes a stationary contact member 187 and a movable contact member188 which are held in a normally closed position with respect to eachother by an overcenter biasing spring 196 until the limits of rotortravel of the rotor member 39 are reached and then said contact membersbecome open circuited or disengaged with respect to each other tothereby prevent the control circuit or means 40 from continuing toenergize either the drive motor 60 or the drive motor 70. The movablecontact member 188 is actuated by a spring arm 197 which is engaged byone of the projections 195.

In order to provide a resilient mounting for the drive motors 6t and 70and to substantially eliminate any alignment requirements in themechanical coupling between the drive motors 6t and 70 and the rotormember 39, the drive motors 60 and 70 are mounted or disposed betweentwo layers or blocks 129 formed from a resilient, elastomeric,rubber-like material, such as sponge neoprene synthetic rubber which are.held in place between the channel member 174 and the lower supportingplate 136 by the bolt 175, as previously explained. The layers or blocks129 also serve to absorb at least a portion of the sound level thatwould otherwise be transmitted to the casing 28 of the inductionregulator 30.

Referring now to FIGS. 13 and 14, the operation of the inductionregulator 30 will be considered for different operating positions of therotor member 39 with respect to the stator core 90. Referring first toFIG. 13 and the schematic diagram of FIG. 16, the rotor member 39 isshown for the position when the mutual inductance between the primarywinding 37 and the secondary winding 35 is at a maximum value. In otherwords, when a voltage is applied at the input terminals 32 and 34 of theinduction regulator 30 and current flows through the primary winding 37and the secondary winding sections 35A and 35B, the magnetic axes of theprimary winding 37 and the secondary winding sections 35A and 35B willbe substantially in line, and the voltages induced in the secondarywinding sections 35A and 358 will be at maximum values and eitheradditive or subtractive with respect to the voltage applied at the inputterminals 32 and 34 of the induction regulator 30. The position of therotor member 39 in FIG. 13 is the maximum boosting position since thevoltages induced in the secondary winding sections 35A and 35B will beadditive and at substantially maximum values for the assumedinstantaneous magnetic flux directions indicated by the dotted and solidarrows shown in FIG. 13. The magnetic fluxes represented by the solidarrows are those produced by the current flow through the primarywinding 37 which is disposed on the rotor member 39. The dotted arrowsshown in FIG. 13 represent the magnetic fluxes produced by the currentswhich flow through the conductor turns of the respective secondarywinding sections 35A and 35B and which are induced in said secondarywinding sections by the current which flows in the primary winding 37and the corresponding magnetic fluxes produced thereby. The maximumbucking position of the rotor member 39 will result when the rotormember 39 is rotated about its central axis substantially from theposition shown in FIG. 13. The induced voltages in the secondary windingsections 35A and 353 would then also be at maximum values and opposingwith respect to the voltage applied at the input isease terminals 32 and34 of the induction regulator 3%. For positions between the maximumboosting and maximum bucking positions of the rotor member 39, thevoltages induced in the secondary winding sections 35A and 353 will becorrespondingly reduced to provide a continuous stepless variation inthe output voltage of the induction regulator 3%. It is to be noted thatwhen mutual inductance exists between the primarywinding 37 and thesecondary winding sections 35A and 35B such as in the maximum bucking ormaximum boosting positions, the ampereturns produced by current flow inthe secondary winding sections 35A and 35B are opposed by theampere-turns produced by the current flow in the primary winding 37 tothereby reduce the eifective impedance of the induction regulator 36 andthe corresponding voltage drop produced across the effective impedanceof said regulator by the load current flow through said regulator to theload circuit at the load conductors L1 and L2.

Referring to FIG. 14, the rotor member 3/ is shown in the neutralposition when the mutual inductance between the primary winding 37 andthe secondary winding sections 35A and 35B is substantially negligible,since the magnetic axes of the primary winding 37 and the secondarywinding sections 35Awand 35B are disposed at substantially right anglesor 90 with respect to one another. If it were not for the improvedconstruction of the induction regulator 30, when load current flowed inthe secondary winding sections 35A and 358 in the neutral position ofthe rotor member 39 shown in FIG. 14, the ampere-turns of the secondarysections would be unopposed and the effective through impedance of theinduction regulator 3% would therefore be greatly increased and thecorresponding through voltage drop in the induction regulatorwouldtialso be increased. The instantaneous assumed directions of themagnetic fluxes produced by current flow in the primary winding 37 areindicated by the solid arrows while the instantaneous magnetic fluxdirections produced by current flow in the secondary winding sections Aand 35B are indicated by the dotted arrows. Considering the magneticpaths around the portion of the conductor turns of the secondary windingsections 35A and 353 in each of the stator slots 64, it will be seenthat the eifective magnetic reluctance in each of the latter magneticpaths will be substantially increased by the air gaps 77 which areintroduced in the latter magnetic paths by the increased width of therotor slots 49 and 51 and the relative position of the stator slots 64and the conductor turns of the secondary winding sections 35A and 35B,which are disposed therein. In other words, the magnetic flux which maysurround the portion of the conductor turns of each of the secondarywinding sections 35A and 353 in each of the stator slots 64 is reducedand the corresponding selfimpedance or leakage reactance of each of thesecondary winding sections 35A and 35B is effectively reduced to therebyreduce the through voltage drop in the induction voltage regulator 30without the use of tertiary windings, as employed in a conventionalinduction regulator structure. It is also to be noted that the magneticfluxes produced by current flow in the upper portion of the conductorturns in the upper stator slot 64 in each of the secondary windingsections 35A and 35B are opposed by the magnetic fluxes produced bycurrent iiow in the portion of the conductor turns of each of saidWinding sections in the lower stator slots of the stator core 94 tothereby increase the effective reluctance of the magnetic paths whichwould otherwise be available through the rotor member 39 to increase theeffective impedance of the regulator 30 in the neutral position. Insummary, the through voltage drop of the induction regulator Ed isreduced in the neutral position without the use of tertiary windings byreducing the magnetic flux which is permitted to surround the individualconductor turns of each of the secondary winding sections 35A and 3513by increasing the relative Width of the rotor slots 4& and 51 i2 ascompared with the circumferential distance between the symmetricallydisposed stator slots 64. In addition, the position of the stator slots64 is arranged to introduce an air gap in the magnetic path around theconductor turns of each of the stator slots 6 in cooperation with theincreased width of the rotor slots 49 and 51.

Referring to FIG. 15, the variation of the induced voltage in one of thesecondary winding sections 35A and 355 from the starting turn to thefinishing turn of said winding section is indicated by the curves 210,236 and 226 for the maximum boosting, maximum bucking and neutralpositions, respectively. It is to be noted that the voltage dropresulting in the secondary winding sections in the neutral position asindicated by the curve 220 is substantially negligible from the startingturn to the finishing turn because of the rotor and stator corestructure just described.

Referring now to FIG. 16, the control circuit or means 4% will now bedescribed in detail. The control circuit or means it? includes thevoltage sensing or error detecting circuit SC and the raise and lowercircuits RC and LC, respectively, for energizing the drive motors ti and79, respectively, in response to the output voltage of the inductionregulator 34) to thereby maintain said output voltage at substantially apredetermined value or within a substantially predetermined operatingrange. As previously mentioned, the control circuit or means 4% isdisposed inside the casing 28 on the side of the barrier members 162 and163 away from the stator core and the rotor member 39 and is connectedin circuit relation with the drive motors 6t) and 7d and the transformer50 by the disconnect plug member 86, which includes a male portion orplug 855A and a female portion or receptacle 803. The disconnect plugmember 8% permits replacing or disconnecting the control circuit ormeans 40 without disturbing the balance of the induction regulator 3th.The disconnect plug member includes a plurality of terminals M1 throughM9 on the male portion thereof and a plurality of correspondingterminals F1 through F9, respectively, on the female portion thereof, asbest shown in FIG. 16. It should be noted that all the components of thecontrol circuit. or means 49 which will be described may be disposed ina container and then impregnated or potted with a suitable thermosettingresin, such as an epoxy resin and then cured in place to provide acompletely sealed unitary member which is immersed in the dielectricfluid inside the casing 28.

More specifically, the sensing circuit SC comprises a full waverectifier 312 whose input terminals are connected across the secondarywinding 58. of the transformer 59 through the current limiting resistor323 to obtain an input signal which varies with or is proportional tothe output voltage of the induction regulator 35? at the terminals 36and 38. The output terminals of the full wave rectifier 312 areconnected in circuit relation with a filtering network which includesthe capacitors 326 and 32d and the resistors 322 and 328. The filteredunidirectional output voltage of the full wave rectifier 312 is thenapplied to the conductors GL1 and CL3 through a temperature compensatingnetwork, which includes the temperature compensating device 336 and theresistor 338. The temperature compensating device may be of anyconventional type, such as a thermistor, and serves in cooperation withthe resistor 338 to temperature compensate the entire control circuit40. The unidirectional voltage or signal which appears at the conductorsCLi and CL3 is therefore a measure of the output voltage of theinduction regulator 34 at the terminals 36 and 38.

In order to obtain an error or difference signal which is a measure ofthe deviation of the output voltage of the induction regulator 3% from adesired regulated value, the unidirectional voltage at the conductorsCL} and GL3 of the sensing circuit SC is applied across a first seriescircuit which includes a voltage reference device,

more specifically the semiconductor diode 320 and the current limitingresistor 352 which are connected in series circuit relation with oneanother between the conductors GL1 and GL3. The diode 320 is preferablyof the type known to the art as a Zener diode and includes a substantially constant voltage region in its reverse voltagecurrentcharacteristic. Since the voltage at the conductors GL3 is positive withrespect to the voltage at the conduotor GL1, the diode 320 is poled in areverse direction and the voltage applied to said diode is always inexcess of a predetermined breakdown voltage above which the voltageacross said diode remains substantially constant to establish asubstantially constant voltage between the conductor GL1 and theconductor GL2 which is connected to the junction between said diode andthe current limiting resistor 352. The voltage at the conductors GL1 andGL3 is also applied to the first and second voltage dividing networkswhich, in general, are connected in parallel circuit relation with theseries circuit which includes the diode 320 and the resistor 352. Thefirst voltage dividing network includes the resistor 344 and thepotentiometer 354 which are connected in series circuit relationshipwith one another between the conductors GL1 and GL3, while the secondvoltage dividing network includes the resistor 342 and the potentiometer346 which are connected in series circuit relation with one anotherbetween the conductors GL1 and the conductor GL3. Since the voltagebetween the conductors GL1 and the conductor GL2 across the diode 320remains sub stantially constant, while the voltages between theconductor GL1 and the arms of each of the potentiometers 346 and 354vary with the output voltage of the induction. regulator, a differencesignal will result between the conductor CD1 and the arms of each of thepotentiorneters 346 and 354.

The setting of the potentiometer arm of the potentiometer 346 will beadjusted to establish a lower limit for the output voltage of theinduction regulator 30, while the setting of the arm of thepotentiometer 354 will be adjusted to establish an upper limit for theoutput voltage of the induction regulator 30. In other words, thesettings of the potentiometers 346 and 354 are adjusted to establish abandwidth or operating range of the output voltage of the inductionregulator 30. In the .operation of the induct-ion regulator 30, when theoutput voltage of the regulator 30 tends to decrease, the differencebet-ween the voltage across the diode 320 and the volt-age between theconductor GL1 and the arm of the potentiometer 346 will increase tothereby actuate the raise circuit RC which will then energize the drivemotor 60 and rotate the rotor member 39 of the regulator 30 until theoutput voltage of the regulator 30 is restored to the lower limit of thedesired operating range. On

the other hand, when the output voltage of the regulator 30 tends. toincrease, the dilference between the voltage across the diode 320 andthe voltage between the conductor GL1 and the arm of the potentiometer354 will increase, until the lower circuit LG is actuated to energizethe drive motor 7ttwhich will then rotate the rotor member 39 of theregulator in the opposite di rection to reduce the output voltage oi theregulator 30 to the upper limit of the desired operating range.

In general, the raise circuit RC comprises a plurality of NOT logicelements, more specifically the switching transistors T1 and T2 whichare arranged to control the operation of a switching device, morespecifically the switching transistor T3 to energize the drive motor 60through the full-wave rectifier 314.

In particular, each of the switching transistors T1, T2 and T 3 includesa base, an emitter, and a collector. The base of the first switchingtransistor T1 is connected to the arm of the potentiometer 346 throughthe current limiting or biasing resistor 348 while the emitter of thetransistor T1 is connected to the conductor GL2. The collector of thetransistor T1 is connected through the resistor 38?. to the negativeoutput terminal of the fullwave rectifier 3 16 whose input terminals areconnected in series circuit relation with the main winding 72 of thedrive motor 70, the latter series circuit being connected across thesecondary winding 54 of the transformer 50. The collector of thetransistor T1 is also directly connected to the base of the transistorT2 while the emitter of the transistor T2 is directly connected to theconductor GL2. Similarly to the first transistor T1, the collector ofthe second transistor T2 is connected to the resistor 358 to thenegative output terminal of the full-wave rectifier 316. The collectorof the transistor T2 is also connected through the feedback resistor 372 to the base of the first transistor T1 to provide bistable operationof the transistors "D1 and T2 and to cut down or reduce the transitiontime between the different conduction stages of the transistors T1 andT2 during operation. .The collector or the transistor T2 is alsodirectly connectedto the base of the third switching transistor T3. Thecollector of the transistor T3 is connected to the negative outputterminal of the full-wave rectifier 314 whose input terminals areconnected in series circuit relationship with the main winding 62 of thedrive motor 60, the latter series circuit being connected across thesecondary winding 56 of the transformer 50. The emitter of thetransistor T3 is connected through the diode 394, the movable contact 188 of the first limit switch LS1, through the stationary contact 18 7 ofthe latter limit switch to the positive output terminal of the fullwaverecifier 314 which is also connected to the positive output terminal ofthe full-wave rectifier 316 and the conductor GL2. The collector of thetransistor T3 is also connected to the feedback resistor 356 to the baseof the transistor T2 in order to reduce the transition time during thedifferent conduction stages of the transistors T2 and T3 during theoperation thereof. The base of the transistor T3 is connected to theconductor GL2 through the resistor 37 8, while a voltage suppressioncircuit or stabilizing network, comprising the resistor 384 and thecapacitor 386 connected in series circuit relationship with one another,is connected between the conductor GL2 and the collector of thetransistor T3.

In the operation of the raise circuit RC, the first and third switchingtransistors T1 and T3 are normally arranged to be substantially cut-offor non-conducting in the absence of a sufficient input signal betweenthe base and the emitter of the first transistor T 1. The input signalbetween the base and the emitter of the first transistor T1 isdetermined by the difference between the voltage across the diode 320and the voltage between the conductor GL1 and the arm of thepotentiometer 346. As long asthe output voltage of the inductionregulator 30 at the terminals 36 and 38, as sensed by the transformer50, remains above substantially a predetermined lower limit, the latterdifference voltage will either be insufficient or the improper polarityto turn the first switching transistor TI on to thereby cause the firsttransistor T1 to carry saturation current and reverse the conductionstates of the transistors T2 and T3. The effective impedance between theemitter and collector of the third switching transistor T3 which iseffectively connected between the negative and positive output terminalsof the full wave rectifier 314 will therefore remain relatively high andthe drive motor 60 will remain deenergized since a corresponding highimpedance will appear across the input terminals of the full-waverectifier 314 which is connected between the secondary winding 56 of thetransformer 50 and the winding 62 of the motor 60. When, however, theoutput voltage of the induction regulator at the terminals 36 and 38decreases to a value below the substantially predetermined lower limitas determined by the setting of the potentiometer 346, the diflerencevoltage between the base and the emitter of the first switchingtransistor T1 will become sufiicient to change the conduction state ofthe first transistor T1 from a substantially cut-01f or non-conductingcondition to an on condition in whic the first transistor T1 will carrysaturation current between the emitter and collector thereof to therebychange the second transistor T2 to a substantially non-conducting torcut-off condition and the third transistor T3 to a subs-tantially oncondition in which the third transistor T3 will carry saturation currentbetween the emitter and collector thereof. The effective impedance inthe emittercollector path of the transistor T3 will therefore decreaseto decrease the effective impedance between the secondary winding 56 andthe winding 62 of the motor as and the motor 6% will be energized fromthe transformer 51 The drive motor 61) will then rotate the rotor member39 of the induction regulator to increasethe output voltage of theregulator 3d at the terminals 36 and 38 until the difference signal atthe input of the first transistor T1 decreases to a value below thatnecessary to maintain the first transistor T1 in a conducting state inwhich it is carrying saturation cunrent between the emitter andcollector thereof.

Similarly, the lower circuit LC includes a plurality of NOT logicelements, more specifically the switching transistors T11 through T14,which in general are connected in circuit relation between the sensingcircuit SC and the drive motor 70 to energize the latter drive motorwhenever the output voltage of the induction regulator 31 exceedssubstantially a predetermined upper limit.

More specifically, the base of the switching transistor T11 is connectedto the arm of the potentiometer 354 through the current limitingresistor 362 while the emitter of the transistor T11 is connecteddirectly to the conductor CL2. The collector of the transistor T11 isdirectly connected to the base of the transistor T12 and also throughthe resistor 364 to the negative terminal of the full-wave rectifier 314. The emitter of the transistor T12 is directly connected to theconductor CL2,'while the collector of the transistor T12 is connected tothe negative terminal of the full-wave rectifier 314 through theresistor 368. The collector of the transistor T12 is also connected tothe feedback resistor 366 to the base of the transistor T11 in order toreduce the transition time between the different conduction states ofthe transistors T11 and T12 during operation. The collector of thetransistor T12 is also directly connected to the base of the transistorT13 while the emitter of the transistor T13 is directly connected to theconductors CLZ. The collector of the transistor T13 is connected to theresistor 376 to a negative terminal of the full-wave rectifier 314 andalso through the feedback resistor 374 to the base of the transistor T12in order to reduce the transistion time between the different conductingstages of the transistors T12 and T13 during the operation thereof. Thecollector of the transistor T13 is also directly connected to the baseof the transistor T14 while the collector of the transistor T14 isdirectly connected to the negative terminal of the full wave rectifier316. The emitter of the transistor T14 is connected through the diode3%, the stationary contact 187 of the second limit switch LS2, and themovable contact 188 of the latter limit switch to the positive terminalof the full-wave recti fier 316. The base of the transistor T14 isconnected to the conductor CL2 through the resistor 398, while a voltagesuppression or stabilizing network, which includes the resistor 392 andthe capacitor 388 connected in series circuit relationship with oneanother, is connected between the conductor CL2 and the collector of thetransistor T14.

In the operation of the lower circuit LC, the transistors T11 and T13are arranged to be normally conducting saturation current in the absenceof a sufficient input signal between the base and the emitter of thefirst switching transistor T11, while the switching transistors T12 andT14 are normally arranged to be substantially non-eonducting or cutoffin the absence of a sufficient input signal between the base and theemitter of the switching transistor T11. The efifective impedancebetween the emitter and collector of the final switching transistor T14of the lower circuit LC, therefore, similarly provides an effectiverelatively high impedance between the negative and positive terminals ofthe full-wave rectifier 31 6 and introduces an effectively highimpedance in series circuit relationship with the main winding i2 of themotor 71 to maintain the motor 711 in a substantially deenergizedcondition in the absence of the necessary input signal between the baseand the emitter of the transistor T11. The input signal between the baseand the emitter of the switching transistor T11 is the differencebetween the voltage across the semiconductor diode 321 and the voltagebetween the con ductor CL]; and the arm of the potentiometer 354. Aslong as the output voltage of the induction regulator 39 at theterminals 36 and remains below substantially a predetermined desiredupper limit, the latter difference voltage is sufficient to maintain thefirst switching transistor T11 in an on condition in which it isconducting substantially saturation current between the emitter and thecollector thereof. When, however, the output voltage of the inductionregulator increases to a value above the desired upper limit, the inputvoltage applied to the switching transistor T11 decreases to a valuebelow that necessary to maintain the switching transistor T11 in an oncondition in which it is conducting saturation current between theemitter and the collector thereof. During the latter operatingcondition, the following switching transistors are actuated to oppositeconduction states so that the switching transistors T11 and T 1 4 areturned on or begin to conduct saturation current between the emitter andcollector thereof, while the switching transistor T13 is actuated tosubstantially a non-conducting or cut off condition. When the switchingtransistor T14 is turned on and begins to conduct saturation currentbetween the emitter and collector thereof and the effective impedancebetween the emitter and collector is reduced to a relatively low value,the corresponding impedance across the input terminals of the full-waverectifier 316 is also reduced to a relatively low value, so that thevoltage applied to the main winding 72 of the drive motor 7% issufiicient to energize the drive motor "76. The drive motor 70 thenrotates the rotor member 39 of the induction regulator 30 until theoutput voltage of the regulator 30 has decreased to a value below thedesired upper limit. The difference input voltage between the base andthe emitter of the switching transistor T11 then increases to the valuenecessary to restore the switching transistor to an on condition and thefollowing switching transistors are actuated to opposite conduct-ionstates, the switching transistor T14 being restored to a substantiallynon-conducting or cut off condition and the motor 71) is thendeenergized. It should .be noted that the additional switchingtransistor stage. is required in the lower circuit LC since the outputvoltage of the induction regulator is changing in a direction which isopposite to that which actuates the raised circuit RC and the additionalswitching transistor stage is necessary to provide the proper outputphase from the lower circuit LC. It should also be noted that theswitching transistors T1 through T3 and T11 through T14 may be describedas NOT logic elements since each of said switching transistors isarranged to provide an effective output in the absence of a particularinput and not to provide an output when the input is of a particularvalue.

In order to protect the control circuits 40 from surge or abnormalvoltages which might result in the induction regulator 34) duringcertain operating conditions, the diodes which make up each of thefull-wave rectifiers 312, 314 and 316 are preferably semiconductordiodes. In other words, the semiconductor diodes which make up each ofthe latter full-wave rectifiers, such as those of the silicon type,include a substantially constant voltage region in their reversevoltage-current characteristics so that when the applied voltage exceedssubstantially a predetermined breakdown voltage, the output voltageacross the diodes remains substantially constant or at a limited value.In addition, the current limiting resistor 323 cooperates with thediodes which make up the full-wave rectifier 312 to limit the surge orabnormal voltages which are applied to the control circuit 40, while thewindings 62 and 72 of the drive motors 60 and 70, respectively,cooperate with the diodes which make up the full-wave rectifiers 3-14and 316, respectively, to also limit the surge or abnormal voltageswhich are applied to the control circuit 40 from the isolatingtransformer 58, which in itself additionally reduces the magnitude ofany abnormal voltages which might be transmitted from the load circuitat the load conductors L1 and L2 from the induction regulator 30.

It is to be understood that the induction regulator as disclosed may beapplied on either two-wire singlephase load circuits or on three-wiresingle-phase load circuits, as previously indicated, since the use ofthe first and second secondary winding sections A and 35B permitssubstantially balanced regulation of the voltages in .a three-wire loadcircuit in which the voltage between the outer conductors thereof issubstantially twice the voltage between the grounded or mid-tappedconductor. It is also to be understood that other types of staticswitching devices may be substituted for the switching transistors T1through T3, and T11 through T14 in a particular application, such asthose of the magnetic amplifier type or those of the electronic tubetype. It is also to be understood that other types of conventional limitswitches may be substituted for the first and second limit switches LS1and LS2 which are connected to interrupt the emitter-collector circuitsof the final switching transistors T3 and T14 of the raise and lowercircuits RC and LC, respectively, as shown in FIG. 16 or that projectingmembers could be provided on the rotor member 39 which would engagecorresponding projecting members on the stationary parts of theregulator to mechanically stop the rotation of the rotor member incertain limiting positions to eliminate the need for the limit switchesLS1 and LS2. It is to be understood that other. types of controlcircuits may be substituted for the control circuit 40 shown in FIG. 16in an overall induction regulator equipment embodying certain featuresof the invention.

The apparatus embodying the teachings of this invention has severaladvantages. For example, the through voltage drop of an inductionregulator as disclosed is reduced to a relatively low value in theneutral position without requiring the use of a separate tertiarywinding on the rotor member thereof as employed in a conventionalinduction regulator. The latter construction feature permits a morecompact design in which both the size and Weight of the inductionregulator are reduced. In addition, the temperature compensationproblems which would otherwise be greater in the control circuit 49 arereduced by the separation of the casing of the induction regulator 36into at least first and second compartments as disclosed. The variousbearing arrangements disclosed for the induction regulator 34 alsoprovide certain advantages with respect to the elimination orfacilitation of alignment, both radial and axial, of the rotor member 39with respect to the inner opening of bore 53 of the stator core 90 inthe induction regulator 39. Finally, the control circuit by means 40 isprotected against the abnormal or surge volttages which might otherwisecause damage thereto by the various circuit arrangements disclosed.

Since numerous changes may be made in the above-described apparatus andcircuits, and different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof, it is intended that all thematter contained in the foregoing description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

We claim as our invention:

1. An induction voltage regulator comprising a laminated hollow statorcore having at least four longitudinal slots therein, a rotor memberdisposed to be angularly positioned inside said stator core and havingat least one pair of longitudinal slots therein, a primary windingdisposed in the slots of said rotor member, said primary winding havingonly one magnetic axis, a secondary winding including at least first andsecond winding sections disposed in the slots of said stator core, saidsecondary winding having only one magnetic axis, one end of each of saidsecondary winding sections being connected to different ends of saidprimary winding, said rotor having a neutral position in which themagnetic axis of the primary winding is perpendicular to the magneticaxis of the secondary winding, the width of each of the slots in saidrotor member being greater than the distance between the adjacent slotsof said stator core to reduce the leakage reactance of each of saidsecondary winding sections in the neutral position of said rotor member.

2. An induction voltage regulator comprising a laminated hollow statorcore having four longitudinal slots therein, said slots beingcircurnferentially displaced from one another around the inner peripheryof said stator core by substantially equal distances, a rotor memberdisposed for angular rotation inside said stator core and having atleast one pair of longitudinal slots therein, a primary Winding disposedin the slots of said rotor member, said primary winding having only onemagnetic axis, and a secondary winding having at least on pair ofwinding sections disposed in the slots of said stator core, saidsecondary winding having only one magnetic axis, the winding sections ofsaid secondary winding being connected in circuit relation with saidprimary winding, the width of the slots of said rotor member beinggreater than the distance between the adjacent slots of said stator coreto reduce the voltage drop in said secondary winding when current flowstherethrough and when the magnetic axes of said primary and secondarywindings are at substantially right angles with respect to one another.

3. An induction regulator comprising a laminated Stator core having asubstantially circular opening therethrough and four slots therein, saidslots being displaced from one another around said opening by an angleof substantially degrees with respect to a central axis, a rotor memberdisposed for angular rotation inside the opening of said stator core andincluding two longitudinal slots thereon on opposite sides of said rotormember, a primary Winding disposed in the slots of said rotor member,said primary winding having only one magnetic axis, a secondary windinghaving first and second winding sections disposed in the slots of saidstator core and connected in circuit relation with said primary winding,said secondary winding having only one magnetc axis, said rotor having aneutral position in which the magnetic axis of the primary winding isperpendicular to the magnetic axis of the secondary winding, the Widthof each of the slots of said rotor member being greater than thecircumferential distance between the adjacent slots of said stator coreto reduce the leakage reactance of said secondary winding when saidrotor is in said neutral position and the magnetic coupling between saidprimary and secondary windings is negligible.

4. An induction regulator comprising a stator, a rotor including taperedshaft portions at each end thereof, said rotor being subjected to avibratory torque during operation of the regulator, a bearing housingdisposed around each of said tapered shaft portions and supported bysaid stator, a split ring bearing member disposed in each bearinghousing and including an inner tapered portion to match that of theassociated shaft portion, a biasing spring disposed in the bearinghousing at one end of said rotor to bear against one of the bearingmembers to apply a frictional force to said shaft portions and opposesaid vibratory torque.

5. An induction regulator comprising a stator formed from a plurality ofstacked laminations of magnetic material, a rotor formed of a pluralityof stacked laminations of magnetic material and including tapered shaftportions at each end thereof, said rotor being subjected to a vibratorytorque during operation of the regulator, the laminations of said rotorand stator being each bonded together with a thermosetting resin, abearing housing disposed around each of said tapered shaft portions andsupported by said stator, a split ring bearing member disposed in eachbearing housing and including an inner tapered portion to match that or"the associated shaft portion, a biasing spring disposed in the bearinghousing at one end of said rotor to bear against one of the bearingmembers to apply a frictional force to said shaft portions and opposesaid vibratory torque.

6. An induction voltage regulator comprising a stator core having asubstantially circular opening therethrough with a plurality oflongitudinal slots therein, a generally cylindrical rotor member havingat least one pair of longitudinal slots on its outer periphery, aprimary winding disposed in the slots of said rotor member, a secondaryWinding disposed in the slots of said stator core, an end bell membersecured to each end of said rotor member at the outer periphery thereofbeyond the slots in the rotor member, each of said end bell membershaving a stub shaft extending therefrom, said end bell members beingshaped to provide clearance spaces between the end bell members and theends of the rotor member to permit winding of said primary Winding inthe slots in the central portion of said rotor member and in theclearance spaces provided by the end bells.

7. An induction voltage regulator comprising a stator core formed from aplurality of laminations of magnetic material and having a substantiallycircular opening therethrough with a plurality of longitudinal slotstherein, a

generally cylindrical rotor member formed from a plurality oflaminations of magnetic material and having at least one pair oflongitudinal slots on its outer periphery, the laminations of saidstator core member being bonded together with a thermosetting resin, thelaminations of said rotor member being bonded together with athermosetting resin, at primary winding disposed in the slots of saidrotor member, a secondary Winding disposed in the slots of said statorcore, an end bell member secured to each end of said rotor member at theouter periphery thereof beyond the slots in the rotor member, each ofsaid end bell members having a stub shaft extending therefrom, said endbell members being shaped to provide clearance spaces between the endbell members and the ends of the rotor member to permit Winding of saidprimary Winding in the slots in the rotor member and in the clearancespaces provided by the end bell members.

References Cited by the Examiner UNITED STATES PATENTS 1,858,845 5/32Nolfert 336-120 X 1,964,265 6/34 Markley 336-120 X 2,294,712 9/42 Bolte336-94 2,671,886 3/54 Smith 336-120 2,838,737 6/58 Duncan 336-1202,915,720 12/59 Mueller 336- X 2,931,969 4/60 Hilkfil 323-66 2,974,2713/61 Guth et a1. 323-66 3,030,597 4/62 Piaia 336-96 JOHN F. BURNS,Primary Examiner.

ORIS L. RADER, Examiner.

1. AN INDUCTION VOLTAGE REGULATOR COMPRISING A LAMINATED HOLLOW STATORCORE HAVING AT LEAST FOUR LONGITUDINAL SLOTS THEREIN, A ROTOR MEMBERDISPOSED TO BE ANGULARLY POSITIONED INSIDE SAID STATOR CORE AND HAVINGAT LEAST ONE PAIR OF LONGITUDINAL SLOTS THEREIN, A PRIMARY WINDINGDISPOSED IN THE SLOTS OF SAID ROTOR MEMBER, SAID PRIMARY WINDING HAVINGONLY ONE MAGNETIC AXIS, A SECONDARY WINDING INCLUDING AT LEAST FIRST ANDSECOND WINDING SECTIONS DISPOSED IN THE SLOTS OF SAID STATOR CORE, SAIDSECONDARY WINDING HAVING ONLY ONE MAGNETIC AXIS, ONE END OF EACH OF SAIDSECONDARY WINDING SECTIONS BEING CONNECTED TO DIFFERENT ENDS OF SAIDPRIMARY WINDING, SAID ROTOR HAVING A NEUTRAL POSITION IN WHICH THEMAGNETIC AXIS OF THE PRIMARY WINDING IS PERPENDICULAR TO THE MAGNETICAXIS OF THE SECONDARY WINDING, THE WIDTH OF EACH OF THE SLOTS IN SAIDROTOR MEMBER BEING GREATER THAN THE DISTANCE BETWEEN THE ADJACENT SLOTSOF SAID STATOR CORE TO REDUCE THE LEAKAGE REACTANCE OF EACH OF SAIDSECONDARY WINDING SECTIONS IN THE NEUTRAL POSITION OF SAID ROTOR MEMBER.